Story highlights

Fernando Benitez: "Those first 96 hours" in a Mexican criminal case are crucial

Tahmooressi was detained in March by border officials for firearms in his possession

"I believe he was denied several basic human rights," Benitez says

A U.S. Marine Corps reservist held in a Mexican prison for more than three months on a weapons charge could have been released within days of his detention if not for "missed opportunities" by his original legal counsel, his attorney told CNN.

In an exclusive phone interview, Fernando Benitez -- the latest attorney for jailed Sgt. Andrew Tahmooressi -- said his client's case was allowed to "simmer" by his original attorneys. They have since been fired.

"For anybody being involved in a criminal case in Mexico, the first 96 hours ... those first 96 hours are crucial," Benitez said. "A lot can be done, and releases can and are obtained regularly, but you have to aggressively address a defensive strategy."

Now, Benitez says, his client is at the mercy of the Mexican judicial system, and there is no timetable for his release.

Tahmooressi has maintained that he took a wrong turn on the California side of the border into Tijuana, Mexico, the night of March 31. His mother told CNN in May that Tahmooressi, who served in Afghanistan, had moved to the San Ysidro, California, area to get treatment for post-traumatic stress disorder.

JUST WATCHED

Mom begs State Department to help son

MUST WATCH

Mom begs State Department to help son 05:36

PLAY VIDEO

Americans detained abroad 23 photos

Americans detained abroad23 photos

Jason Rezaian – Jason Rezaian, The Washington Post bureau chief in Tehran; his wife Yeganeh Salehi and two freelance journalists were detained on July 22, 2014, according to the newspaper. An Iranian official confirmed to CNN at the time that the group was being held by authorities but did not say what they were charged with.

Hide Caption

1 of 23

Americans detained abroad23 photos

Saeed Abedini – A 33-year-old U.S. citizen of Iranian birth, Abedini was sentenced to eight years in prison in January 2013. He was accused of attempting to undermine the Iranian government and endangering national security by establishing home churches. He was detained in Iran on September 26, 2012, according to the American Center for Law and Justice.

Hide Caption

2 of 23

Americans detained abroad23 photos

Robert Levinson – Retired FBI agent Robert Levinson has been missing since 2007. His family says he was working as a private investigator in Iran when he disappeared, and multiple reports suggest Levinson may have been working for the CIA. His family told CNN in January that they have long known that Levinson worked for the CIA, and they said it's time for the government to lay out the facts about Levinson's case. U.S. officials have consistently denied publicly that Levinson was working for the government, but they have repeatedly insisted that finding him and bringing him home is a "top" priority. The FBI increased its reward for information on Levinson from $1 million to $5 million, it announced in March.

Hide Caption

3 of 23

Americans detained abroad23 photos

Amir Hekmati – An Iranian court threw out a 2011 death sentence forAmir Hekmati, a former U.S. Marine charged with spying. But he was secretly retried in Iran and convicted of "practical collaboration with the U.S. government," his sister told CNN on April 11. He was sentenced to 10 years in prison, she said. Hekmati was detained in August 2011 during a visit to see his grandmother. His family and the Obama administration deny accusations he was spying for the CIA.

Hide Caption

4 of 23

Americans detained abroad23 photos

Joshua Boyle and Caitlin Coleman – Mothers Linda Boyle, left, and Lyn Coleman hold photo of their married children, Joshua Boyle and Caitlin Coleman, who were kidnapped by the Taliban in late 2012. Coleman was pregnant when she was kidnapped and is believed to have had a child in captivity.

Hide Caption

5 of 23

Americans detained abroad23 photos

Mohamed Soltan – Jailed since 2013 and sentenced to life for supporting the Muslim Brotherhood in Egypt, Mohamed Soltan has been released, the U.S. Embassy in Cairo said on Saturday, May 30, 2015. Soltan's family denies he belonged to the Brotherhood. Soltan had been a dual U.S. and Egyptian citizen, but renounced his Egyptian citizenship as a condition of his release.

Jeffrey Edward Fowle – One of three Americans detained in North Korea, Fowle was released and sent home, a State Department official told CNN on Tuesday, October 21. Fowle was accused of leaving a Bible in a hotel where he was staying. North Korea announced Fowle's detention in June, saying he had violated the law by acting "contrary to the purpose of tourism." Fowle told CNN: "I've admitted my guilt to the government and signed a statement to that effect and requested forgiveness from the people and the government of the DPRK."

Hide Caption

8 of 23

Americans detained abroad23 photos

Kenneth Bae – In May 2013, a North Korean court sentenced Bae, a U.S. citizen, to 15 years of hard labor for committing "hostile acts" against the state. North Korea claimed Bae was part of a Christian plot to overthrow the regime. In a short interview with CNN on Monday, September 1, Bae said he is working eight hours a day, six days a week at a labor camp. "Right now what I can say to my friends and family is, continue to pray for me," he said. After months in detention, he and fellow American detainee Matthew Todd Miller were released in November 2014.

Hide Caption

9 of 23

Americans detained abroad23 photos

Matthew Todd Miller – Miller, the American sentenced to six years of hard labor in North Korea began serving his six-year sentence on September 25. He was one of three Americans detained in North Korea who spoke to CNN's Will Ripley in September 2014 and implored the U.S. government for help. The 24-year-old was accused of tearing up his tourist visa and seeking asylum upon entry. He and Kenneth Bae were released in November 2014.

Hide Caption

10 of 23

Americans detained abroad23 photos

Peter Theo Curtis – American journalist Peter Theo Curtis was handed over to U.N. peacekeepers on August 24 after nearly two years in captivity. He is believed to have been captured in October 2012 and held by the al-Nusra Front, a Syrian rebel group with ties to al Qaeda.

Hide Caption

11 of 23

Americans detained abroad23 photos

Alan Gross – Gross, at right with Rabbi Arthur Schneier was jailed while working as a subcontractor in Cuba in December 2009. Cuban authorities say Gross tried to set up illegal Internet connections on the island. Gross says he was just trying to help connect the Jewish community to the Internet. Former President Jimmy Carter and New Mexico Gov. Bill Richardson both traveled to Cuba on Gross' behalf. He was eventually released in December 2014.

Hide Caption

12 of 23

Americans detained abroad23 photos

Sgt. Bowe Bergdahl – This undated image provided by the U.S. Army shows Bergdahl, who had been held by insurgents in Afghanistan since 2009. The White House announced Bergdahl's release on May 31, 2014. Bergdahl was released in exchange for five senior Taliban members held by the U.S. military. In March the U.S. military charged Bergdahl with one count each of "Desertion with Intent to Shirk Important or Hazardous Duty," and "Misbehavior Before The Enemy by Endangering the Safety of a Command, Unit or Place."

Hide Caption

13 of 23

Americans detained abroad23 photos

Merrill Newman – U.S. tourist and Korean War veteran Merrill Newman arrives at the Beijing airport on December 7, 2013, after being released by North Korea. Newman was detained in October 2013 by North Korean authorities just minutes before he was to depart the country after visiting through an organized tour. His son Jeff Newman said the Palo Alto, California, man had all the proper paperwork and set up his trip through a North Korean-approved travel agency.

Hide Caption

14 of 23

Americans detained abroad23 photos

Yanira Maldonado – Mexican authorities arrested Yanira Maldonado, a U.S. citizen, right, in May 2013, for alleged drug possession. She and her husband, Gary, were traveling from Mexico back to the United States when their bus was stopped and searched. She was released a few days later and is now back in the United States.

Hide Caption

15 of 23

Americans detained abroad23 photos

Laura Ling and Euna Lee – North Korea has arrested Americans before, only to release them after a visit by a prominent dignitary. Journalists Laura Ling, center, and Euna Lee, to her right, spent 140 days in captivity after being charged with illegal entry to conduct a smear campaign. They were freed in 2009 after a trip by former President Bill Clinton.

Hide Caption

16 of 23

Americans detained abroad23 photos

Aijalon Gomes – Former President Jimmy Carter negotiated the release of Aijalon Gomes, who was detained in 2010 after crossing into North Korea illegally from China. Analysts say high-level visits give Pyongyang a propaganda boost and a way to save face when it releases a prisoner.

Hide Caption

17 of 23

Americans detained abroad23 photos

Eddie Yong Su Jun – Detained in April 2011, Junwas released by North Korea a month afterward. His alleged crime was not provided to the media. The American delegation that secured his freedom included Robert King, the U.S. special envoy for North Korean human rights issues.

Hide Caption

18 of 23

Americans detained abroad23 photos

Robert Park – Without any apparent U.S. intervention, Park was released by North Korea in 2010. The Christian missionary crossed into North Korea from China, carrying a letter asking Kim Jong Il to free political prisoners and resign. North Korea's state-run news agency said Park was released after an "admission and sincere repentance of his wrongdoings." Here, Park holds a photo of Kim and a malnourished child during a protest in Seoul.

Hide Caption

19 of 23

Americans detained abroad23 photos

Josh Fattal, Sarah Shourd and Shane Bauer – Josh Fattal, center, Sarah Shourd, left, and Shane Bauer were detained by Iran while hiking near the Iraq-Iran border in July 2009. Iran charged them with illegal entry and espionage. Shourd was released on bail for medical reasons in September 2010; she never returned to face her charges. Bauer and Fattal were convicted in August 2011, but the next month they were released on bail and had their sentences commuted.

Hide Caption

20 of 23

Americans detained abroad23 photos

Haleh Esfandiari – Esfandiari, an Iranian-American scholar, was detained at Iran's Evin Prison, spending months in solitary confinement before Iran released her on bail in August 2007. Esfandiari was visiting her ailing mother in Tehran when she was arrested and charged with harming Iran's national security.

Hide Caption

21 of 23

Americans detained abroad23 photos

Robert Becker – Sixteen Americans were among the dozens arrested in December 2011 when Egypt raided the offices of 10 nongovernmental organizations that it said received illegal foreign financing and were operating without a public license. Many of the employees posted bail and left the country after a travel ban was lifted a few months later. Robert Becker, right, chose to stay and stand trial. He spent two years in prison and has since returned to the U.S.

Hide Caption

22 of 23

Americans detained abroad23 photos

Timothy Tracy – Filmmaker Timothy Tracy was arrested in Venezuela in April 2013 on allegations of funding opponents of newly elected President Nicolas Maduro, successor to the late Hugo Chavez. Tracy went to Venezuela to make a documentary about the political division gripping the country. He was released in June 2013.

Hide Caption

23 of 23

EXPAND GALLERY

He was detained by Mexican border officials for possessing a .45-caliber pistol, a 12-gauge pump shotgun and an AR-15 rifle.

For weeks, Tahmooressi sat in a Tijuana prison while his defense attorneys failed to submit evidence to the court in the initial stages of his defense.

Tahmooressi and his attorneys alleged that he was beaten and tortured by guards and prisoners at the prison. Mexican officials have denied that claim.

He has since been transferred to El Hongo Penitentiary in Tecate, where he told CNN earlier this month that he is being treated well.

Benitez has submitted evidence and will continue to do so between now and August 4, Tahmooressi's next court date. His combined legal bills have already surpassed more than $20,000, according to the family.

"In Andrew's case, several windows of opportunity were missed," Benitez said. "It's frustrating to us. I would have loved to have taken advantage of those opportunities. But now we need to work with what we have and that's exactly what we're going to do."

Germane to Tahmooressi's defense is that Tahmooressi's rights were violated under the Mexican constitution, Benitez said.

"I believe he was denied several basic human rights, which, it's my contention, should result in reparation from the court" in the form of declaring a mistrial or tossing out the testimony "of those officers who are singling him out as the responsible party in this case."

A 20-year criminal defense veteran, Benitez said he has a strong track record of acquittals or cases being thrown out in federal court.

In 2011, he defended former Tijuana Mayor Hank Rhon, whose house was raided by Mexican soldiers who discovered an arsenal of illegal guns and ammunition. Benitez successfully argued that the raid was performed without a warrant. All charges were dropped.

The same should be expected for Tahmooressi's case, Benitez told CNN.

"Andrew's case, believe it or not, is technically not that complex," Benitez said. "It's a mistake many people have made. I've driven my car up to San Diego and back to Tijuana and I can tell you I've made the same mistake he made. And I'm a resident. The evidence we've been uncovering all supports his story."